With Preview off, changes made in the Image Trace panel for one Image
Trace object were lost when another object was selected: selecting the
first object again showed its stored settings. The panel now keeps the
waiting changes for each object and shows them again when that object
is selected, unless the object's own settings changed in the meantime.
When Preview was turned on while another object was selected, the
object is traced with its changes when it is selected again.
Preview is now the UI command imageTrace.preview ({on?}: on, off or
toggle), and both the panel's checkbox and ui.set's imageTracePreview
run it. The command label has a row in every catalog.